I dont see him as a game changer but I think he can be adequate.
My issue with Davis is that his first step is usually back. Like he's trying to get up a head of steam. Meanwhile the gunners or coverage guys are 10-12 yards closer. i cant believe that the coaches never saw this. Makes no sense.
The most important part of being a punt returner is ball security. Davis has never muffed or fumbled a punt. The second most important part is fearlessness, and Davis has that in spades. Add in Davis' elite athletic ability, and you have a hell of a returner. Green Bay isn't looking for Davis' replacement, they're looking for his backups.
Davis doesn't go backwards on his returns, but he does go sideways sometimes so he can hit the holes. Considering he has a career 12 yards-per-return average, I don't mind a couple of sideways steps. And he does hit the holes, 21% of his punt returns go for 20 yards or longer.
The new kickoff coverage rules are going to up his KO return average too. Against Seattle, his first game of the year last year, we got a taste of that when one of his two KO returns went for 55 yards. If we can stop getting penalized on his returns, he might average 30 yards per KO return, and 15 yards per punt return.
Is that adequate enough for you?